The present invention relates to a new variable oleopneumatic shock absorbing device with the possibilty for adjustment, which can be used not only to produce suspension for vehicles such as automobiles, motorcycles and bicycles, but can also be used in all installations requiring the use of a shock absorbing system, such as industrial, agricultural and civil engineering works machinery and tooling, trucks, trailers, lifting and handling gear, and opening or closing systems.
Oleopneumatic shock-absorbing devices are well known and are used in many technical fields.
The solutions put forward to date are, however, relatively complicated, highly sensitive to wear, rapidly lose their effectiveness and often allow shock absorption to be obtained in just one direction. Furthermore, the degree of shock absorption is generally determined at the time of manufacture and it is difficult to effect individual adjustment as required and, more importantly, to effect such an adjustment even during operation.
Now, there has been found, and this is what forms the subject-matter of the present invention, a simple solution which makes it possible to solve these problems, which solution can be used either alone or be incorporated into shock-absorbing and/or suspension assemblies.
Oleopneumatic shock-absorbing devices in general consist of an assembly which is intended to be interposed between a bearing element and a part to be suspended, and essentially includes a cylinder filled with a fluid (for example oil) connected to the bearing element (or to the element to be suspended), and inside which there can move a piston, the rod of which is connected to the bearing element (or to the part to be suspended). The piston has calibrated nozzles equipped with check valves which makes it possible, as the said piston moves, to slow the movements, for example the oscillations of the suspension, to a greater or lesser extent. Furthermore, the piston also contains a second piston known as a "free piston", which allows the definition within the cylinder of a chamber containing a pressurized gas (for example nitrogen).
As indicated earlier, such oleopneumatic shock absorbers are of a complicated design, lose their qualities as soon as they are slightly worn, and do not always make it possible to obtain effective shock absorption, this being the case both in the outward stroke and in the return stroke, nor do they allow adjustment during operation. Furthermore, current shock absorbers attenuate vibration, but this vibration still remains troublesome. Furthermore, the travel engendered by defects of the highway are not well absorbed.